Starting system for internal-combustion engines.



F. KRATZ.

STARTING SYSTEM FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED DEC. I7. I9I4. 1,259,876.

Patented Mar. 19, 1918.

2 SHEETS-SHEET l.

72 IIIIINII i4 vI/ITNIEE-E E5 g z wzaE 2.; 525 /22 fie F. KRATZ.

STARTING SYSTEM FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED DEC. 17. I9I4.

1,259,876. Patented Mar. 19, 1918.

2 SHEETS-SHEET 2.

WITNESS S IBNEIJTUFK UNITED STA 1 ENT FRANZ KRATZ, 0F STUTTGAR'I',GERMANY, ASSIGNOR TO THE FIRM 0F ROBERT BOSCH, 0F STUTTGART, GERMANY.

STARTING SYSTEM FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Mar. 19, 1918.

Application filed December 17, 1914. Serial No. 877,659.

To all whom it may concern."

Be it known that I, FRANZ KRATZ, a subject of the Emperor of Germany,residing at and whose post-ofiice address is Schlosstrasse 59 Stuttgart,Germany, have invented certain new and useful Improvements in StartingSystems for Internal- Combustion Engines; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

In order that the starting system may be automatically released when theinternal combustion engine with which it is associated starts to operateunder its own power, an over-running clutch is sometimes provided fortransmitting the power from the starting motor or hand-crank to theengine. HoWeVer,-if pawls form the connecting element of the clutch,they remain in contact with their ratchet wheel after the engine isunder way, and therefore they wear away rapidly and produce considerablenoise. Likewise, if rollers or balls form the connecting element, theyroll in their cages after the engine is under way, and since they are atthat time rotated at very high speed, they heat and wear excessively.For these reasons, an independently rotatable part has been placedbetween the driving and drivenmembers of the clutch, but in this casethe connecting element remains in contact with both members until thestarting system comes to a standstill, wear and noise resulting duringthe period of retardation of the starting system.

The object of the present invention is to provide a starting system,either with or without a starting motor, wherein disengaging mechanismis provided for holding the connecting element of the over-runningclutch out of contact with the driving or driven member. In thepreferred embodt ment 9f the invention, wherein a starting motor of the,electric, air or other type is used, thestarting system is socoordinated with the disengaging mechanism that when the starting motoris connected to its source of power supply, the connecting element ofthe clutch engages both the driving and the driven members for rotationas a unit to transmit power from the motor to the engine; and when thesource of power is disconnected from the motor, the disengagingFurthermore, where pawls are used as the connecting element of theclutch, the operator is given notice to disconnect the source of powersupply as soon as the engine gets under way, if he should have failed todo so in time.

In the accompanying drawings illustrating the preferred form and severalmodifications within my invention,

Figures 1, 3 and 5 are diagrammatic views of the different embodimentswherein an electric starting motor is used to drive the intermediatedriving shaft of an automobile or motor boat as anexample; and

Figs. 2 and t are partly diagrammatic cross sections of the over-runningclutches shown in Figs. 1 and 3.

In the drawings, the crank shaft 1 of the engine is connected by afriction clutch 2, 3 to the intermediate driving shaft 4., which carriesthe gear 60 in the speed change box in the well known way, and anelectric motor 5 carries a gear 6 operating the driving member '4' ofthe overrunning clutch. The motor is connected to the battery 1:2 by anelectric circuit 24, 25, 26 containing the switch 13.

In the modification shown in Figs. 1 and 2, the over-running clutch hasa driven memher 8, fast on the intermediate shaft i, and a drivingmember 7 resting on the rollers 9 in the cages 10, the springs 11tending to force the rollers into the contracted parts of the taperedpassages of the cages. .The electromagnet 15 is energized from thebattery 12 upon closing the switch 14, and the armature shaft 16, actingagainst the tension spring 23, closes the switch 13 and rocks the forkedlever 17 upon its pivot 18. The driven member 8 carries pivoteddisengaging pawls, each having a tail-piece 21 adapted to press a roller9 into the deep part of the cage out of contact with the driving member7, thereby compressing the spring ii. and completely disengaging thedriving and driven members. Each of the pawls has a projecting portion22 cooperative with the conical surface of the collar 20. The

forked lever 17 engages a slot of the collar, the arrangement being suchthat when the switch 13 is closed, the projecting portions 22 of thedisengaging pawls ride on the low portion 19 of the conical surface, andpermit the rollers 9 to operatively connect the driving and drivenmembers, but when the switch is opened, the disengaging pawls ride onthe high portion 18 of the collar and positively force the rollers 9 outof operative engagement.

Upon closing the switch 14 to start the engine, the switch 13 is closedby the 'electromagnet, whereupon the battery supplies starting currentto the motor. The driving member 7 is then rotated in the direction ofthe arrow in Fig. 2 and the rollers 9 transmit the power from thestarting motor 5 to the intermediate driving shaft 4. At the propertime, the intermediate driving shaft is connected to the crank-shaft ofthe engine by means of the clutch 2, 3. As soon as the engine startsunder its own power, the operator opens switch 14, whereupon switch 13is opened by the spring 23 and the collar 20 is shifted toward the rightin Fig. 1, so that the projecting portions 22 of the disengaging pawlsride upon the high part of the conical surface of the collar and forcethe rollers into the deep parts of the cages. I11 this position therollers are out of contact with the driving member 7 and are, therefore,not rolled in their cages.

In the modification shown in Figs. 3 and 4, there is anindependently-rotatable part 27 mounted on the shaft 4 on theball-bearing 28. This part has a disk portion intermediate the drivingmember 7 and the driven member 8, and carries the pivoted pawls 29. Thedriving member 7 has internal engaging points, and the driven member 8has external engaging points, the pawls 29 being mounted in slots in theintermediate part in such a manner that they may engage the engagingpoints of both members to operatively connect them. The springs 30 arepermitted to force the pawls to their inclined position, shown in Fig.4, out of contact with the driven members, when the brake 32 is notapplied to the friction surface 31. However, when the switch 13 isclosed by the electromagnet, the pivoted lever 17 moves the brake intoengagement with the friction surface 31, retarding the rotation of thedisk 27 relatively to the driving member 7, and thereby turning thepawls 29 on their pivots until they engage the engaging points of thedriven member 8 while still engaging the engaging points of the drivingmember 7. The spring 33 forms a resilient buffer between the armatureshaft 36 of the electromagnet and the pivoted lever 17. As soon as theswitch 13 is opened, the brake 32 is re leased and the springs 30 forcethe pawls out of contact with the engaging points of the driven member8.

In Fig. 5, the speed change lever 34 closes the switch 13, and appliesthe brake 32 to the friction surface 31 of the intermediate part 27,when it is moved to a starting position. At this time, the over-runningclutch transmits power from the motor 5 to the shaft 4. At all otherpositions of the speed change lever, the switch 13 is opened, so thatthe battery is disconnected from the motor.

Having thus described my invention, what I claim is:

1. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven members, a connectingelement movable to connecting position in which the two members rotateas a unit, and disengaging mechanism for the connecting element;starting mechanism for driving the driving member to start the engine;and means which, upon starting the starting mechanism into operation,moves the disengaging mechanism to cause the connecting element to moveinto connecting position, and which, upon discontinuing the operation ofthe starting mechanism, moves the disengaging mechanism to cause theconnecting element to move out of contact with one of the two members.

2. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven members, a connectingelement movable to connecting position in'which the two members rotateas a unit, and disengaging mechanism for the connecting element; astarting motor for driving the driving member to start the engine; andmeans which, upon starting the starting motor into operation, moves thedisengaging mechanism to cause the connecting element to move intoconnecting position, and which, upon discontinuing the operation of thestarting motor, moves the disengaging mechanism to cause the connectingelement to move out of contact with one of the two members.

3. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven mem bers, a connectingelement movable to connecting position in which the two members rotateas a unit, and disengaging mechanism for the connecting element; astarting motor for driving the driving member to start the engine; asource of power supply for the motor; and a contro ler which, uponconnecting the source of power supply to the starting motor, moves thedlsengaging mechanism to cause the connecting element to move intoconnecting position, and which, upon disconnecting the source of powersupply from the motor, moves the disengaging mechanism to cause theconnecting element to move out of contact with one of the two members.

4. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven members, a connectingelement movable to connecting position in which the two members rotateas a unit, and disengaging mechanism for the connecting element; anelectric starting motor for driving the driving member to start theengine; a battery; and a switch which, upon connecting the battery andmotor, moves the disengaging mechanism to cause the connecting elementto move into connecting position, and which, upon disconnecting thebattery from the motor, moves the disengaging mechanism to cause theconnecting element to move out of contact with one of the two members.

5. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven members, a connectingelement movable to connecting I position in which the two members rotateas a unit, and disengaging mechanism for the connecting element; anelectric starting motor for driving the driving member to start theengine; a battery; an electromagnetic switch which, upon energization,connects the battery to the motor and moves the disengaging mechanism tocause the connecting element to move into connecting position, andwhich, upon denergization, disconnects the motor from the battery andmoves the disengaging mechanism to cause the connecting element to moveout of contact with one of the two members.

6. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven members, a connectingelement movable to connecting position in which the two members rotateas a unit, and disengaging mechanism for the connecting element; anelectric starting motor for driving the driving member to start theengine; a battery; an electromagnetic switch which, upon energization,connects the battery to the motor'and moves the disenagaging mechanismto cause the connecting element tomove into connecting position, andwhich, upon deenergization, disconnects the motor from the battery andmoves the disengaging mechanism to cause the connecting element to moveout of contact with one of the two members; and a switch and electricalconnections between the battery and the electromagnetic switch forenergizing the winding thereof at will.

7. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven members, an independentlyrotatable intermediate part, a connecting element carried by theintermediate part and movable to connecting position in which the twomembers rotate as a unit, and disengaging mechanism for the connectingelement; starting mechanism for driving the driving member to start theengine; and means which, upon starting the starting mechanism intooperation, moves the disengaging mechanism to cause the connectingelement; to move into connecting position, and which, upon discontinuingthe operation of the starting mechanism, moves the disengaging mechanismto cause the connecting element to move out of contact with one of thetwo members.

8. In a starting system for internal combustion engines; an overrunningclutch comprising coaxial driving and driven members with opposedengaging points, an independently-rotatable intermediate part, aconnecting element carried by the intermediate part and movable toconnecting position in which the two members rotate as a unit, and aspring tending to hold the connecting element out of contact with theengaging points of one of the two members; a brake adapted tofrictionally contact with the intermediate part to retard its rotationand thereby engage the connecting element with the engaging points ofboth members against the action of the spring; starting mechanism fordriving the driving member to start the engine; and means which, uponstarting the starting mechanism into operation, positively moves thebrake into contact with the intermediate part, and which, upondiscontinuing the operation of the starting mechanism, positively holdsthe brake out of contact with the intermediate part.

In testimony whereof I afiix my signature in presence of two witnesses.

FRANZ KRATZ.

Witnesses:

WILLIAM STRUss, FREDERICK HOYERMAUER.

